IPMAT Rohtak 2019 (QA) PYQs

The value of $\cos^2\left(\frac{\pi}{8}\right) + \cos^2\left(\frac{3\pi}{8}\right) + \cos^2\left(\frac{5\pi}{8}\right) + \cos^2\left(\frac{7\pi}{8}\right)$ is

If a pole 6 m high casts a shadow $2\sqrt{3}$ m long on the ground, then the sun's elevation is

Given that $\cos x + \cos y = 1$, the range of $\sin x - \sin y$ is